1. Field of the Invention
The present invention relates to, particularly, an ink jet recording apparatus which can print an image by emitting a liquid-like ink from a print head and to a control method of such an apparatus and, further, relates to a recording apparatus which can operate by turning on a power source and to a control method of such an apparatus.
2. Related Background Art
Hitherto, there has been a recording apparatus of the ink jet system which can print an image by emitting a liquid-like ink from a print head.
The conventional recording apparatus can operate by turning on a power source and cannot operate when the power source is turned off.
The invention will now be described with respect to a thermal jet system among the ink jet systems as an example.
The thermal jet system will be first explained.
According to the thermal jet system, in case of performing a multicolor printing, four kinds of inks of, for example, Y (yellow), M (magenta), C (cyan) and K (black) are emitted from a print head having a plurality of nozzles to a print paper, a color is reproduced by a color reduction mixture, and the inks are fixed onto a print paper by a natural dry, thereby printing an image.
The print head according to the thermal jet system moves in the direction (right and left directions) perpendicular to the transporting direction of the print paper as shown in FIG. 17.
A method of ejecting the ink will now be described with respect to one of a plurality of nozzles constructing the print head as an example as shown in FIG. 18. The liquid ink is filled in each nozzle as shown in the diagram. A heater to heat the nozzle is provided for every nozzle. First, in step 181, the nozzle is instantaneously heated by the heater, thereby generating bubbles in the inside of the ink as shown in steps 182 to 184. The ink is emitted by a pressure of the bubbles as shown in step 185.
As described above, the print head is constructed by a set of fine nozzles and, as an ink filled in each nozzle, a quick-drying ink is used so that it can be easily fixed onto the paper by the natural dry. Therefore, it is necessary to pay an attention to a choking of nozzles. In a non-printing state, accordingly, the print head is held at a home position shown in FIG. 17 in a standby state and the head is capped in order to prevent that the nozzles are dried, thereby preventing a choking of the nozzle.
However, hitherto, the print head is not always capped due to the relation of the printing operation when the print head is located at the home position. For example, a time interval of a few seconds exists until the print head is capped after the head was returned to the home position after completion of the printing operation. In the case where such a state is seen from the operator, however, the print head has already been returned to the home position and it seems as if the printing process including the capping operation has already been completed. Therefore, there is a serious drawback such that the operator turns off the power source before the print head is capped, so that the capping operation is stopped and the nozzles are left without being capped and the nozzles in the print head are dried and choked and a desired print result cannot be obtained in the next printing operation.
On the other hand, even if the operator has a knowledge of a capping process which is executed to prevent the choking of the nozzles of the print head, operator cannot discriminate whether the print head has been capped or not so long as the print head is merely seen. The operator cannot know how long he must wait for the operation to turn off the power source after the print head was returned to the home position. In case of using a method whereby the operator waits for the operation to turn off the power source until he can presume that the capping operation will have been finished, it is very inconvenient when he wants to turn off the power source as soon as possible.